I finished a draft of a cartesian point/vector for dummies that works with boost::units. Here is an example usage of it. I should be able "tell" boost::geometry how to work with cartesian::point and cartesian::vector, right? Notice how you can't intermingle points from different reference frames (near the bottom of the example). I've attached the source code <snipped headers> using namespace std; using namespace boost; using namespace boost::units; using namespace cartesian; typedef quantity<si::length, point3d > Position; typedef quantity<si::length, vector3d > Displacement; typedef quantity<si::velocity, vector3d > Velocity; typedef quantity<si::time> Time; int main() { static const si::length m = si::meter; static const si::time s = si::second; Position p1 = point3d(1.0, 2.0, 3.0) * m; Position p2 = point3d(4.0, 5.0, 6.0) * m; Position p3 = point3d(3.0, 9.0, 4.0) * m; Displacement disp1(p2 - p1); cout << disp1 << endl; cout << abs(disp1) << endl; cout << abs_squared(disp1) << endl; p1 += disp1; cout << p1 << endl; Time dt(Time(0.1 * s)); Velocity v((p3 - p2) / dt); cout << v << endl; cartesian::vector<4, int> v_move = assign::list_of(3)(-2)(17)(33); cout << "v_move=" << v_move << endl; struct ECEF { }; point<4, int, ECEF> ecef_pt1 = assign::list_of(3)(2)(-10)(-13); point<4, int, ECEF> ecef_pt2 = ecef_pt1 + v_move; cout << ecef_pt1 << ' ' << ecef_pt2 << ' ' << (ecef_pt2 - ecef_pt1) << endl; struct Local { }; point<4, int, Local> local_pt1 = assign::list_of(19)(-18)(17)(-16); point<4, double, Local> local_pt2 = local_pt1 + v_move; cout << local_pt1 << ' ' << local_pt2 << ' ' << (local_pt2 - local_pt1) << endl; // cout << (local_pt1 - ecef_pt1) << endl; // won't compile // Compiles, but is senseless. cout << (local_pt1.from_origin() - ecef_pt1.from_origin()) << endl; return EXIT_SUCCESS; } // main ====== Output ========= <3 3 3> m 5.19615 m 27 m^2 (4 5 6) m <-10 40 -20> m s^-1 v_move=<3 -2 17 33> (3 2 -10 -13) (6 0 7 20) <3 -2 17 33> (19 -18 17 -16) (22 -20 34 17) <3 -2 17 33> <16 -20 27 -3>